The invention relates to a switching device for connection to an antenna unit. The invention also relates to a communication device with a switching device of this type.
For gathering information, for exchanging information and for increasing safety in road traffic, communication systems in which as many road users as possible are involved are subject to development. While communication between motor vehicles, referred to as car-to-car (C2C) communication, is intended to enable communication between motor vehicles via corresponding communication devices, concepts for car-to-X or car-to-environment (car-to-X, C2X) communication are also already known. In particular in this respect, it has been proposed to enable a communication with fixed infrastructure units, for example to enable a communication with traffic lights or the like via a car-to-infrastructure communication.
Communication systems of this type are intended to support wireless ad hoc communication, so that road users can exchange standardized messages via fixed radio frequencies. Particularly the Dedicated Short-Range Communication (DSRC), which provides communication channels and corresponding protocols and standards, is known here. A further approach is the IEEE 802.11p standard, which relates to wireless LAN (WLAN). The use of Bluetooth in local area communication has also already been discussed.
Local area communication between road users offers a multiplicity of functions of reciprocal information provision and warning, for example emergency warning systems for motor vehicles, cooperative ACC, collision avoidance measures and the like, but also simplified infrastructure systems such as electronic parking billing and toll checks.
For communication in a car-to-X communication system, the communication users require a communication device which should comprise an antenna and a facility for data processing to produce the required functions. In DE 10 2010 002 092 A1, it is suggested to use a data preprocessing unit which, for example, does not forward unsuitable data to a safety system or mobility system of a user. DE 10 201 0 029 482 A1 discloses a switching device in the form of an interface device, to which an antenna unit can be connected and which furthermore has an interface to a motor vehicle communication system, for example a CAN bus.
The incorporation of further communication users along with fixed infrastructure units, for example traffic lights and motor vehicles, reveals itself to be problematic. In order, for example, to equip pedestrians or cyclists also with communication devices for car-to-X communication, mobile communication devices would be needed which require in particular a compact structure, but also an adequate power supply. Whereas the antennas used for car-to-X communication are usually quite large, a large amount of power, which requires a corresponding outlay in terms of design and construction, is required to transmit messages and process and evaluate the messages arriving in large numbers.
US 2004/0254690 A1 relates to a modular navigation system module, which is intended for use in various motor vehicles. It is therefore proposed that the module itself recognizes the vehicle type of the vehicle and adapts its information output accordingly. A Bluetooth module, an IEEE 802.11x module and a DSRS module can be present in the same network, a “media oriented system transport” (MOST) network. The Bluetooth module can allow the information exchange of the system with PDAs, mobile telephones and the like.
U.S. Pat. No. 7,596,438 B2 discloses a beacon-based control system in a motor vehicle, which can receive wireless signals from beacons at geographical locations in order to use their information in particular for control in the motor vehicle. An input device to configure the system may comprise a wireless transceiver, for example a mobile telephone, a PDA or a pager. Thus, the motor vehicle can acquire a multiplicity of addable services from a remote control centre through wireless transmission.
The use of the WLAN standard for a C2C communication through the addition of new packet types is described by DE 10 2008 060 231 A1. It is proposed therein to extend the MAC layer of the 802.11 WLAN standard with a data packet type which is ignored by existing WLAN implementations, but can be used by modified implementations to set up an effective C2X communication, after the device to which the respective data frame is transmitted can be selected.
US 2007/0150169 A1 relates to navigation systems, methods and programs dealing with the determination of congestion information of a road connection. Here, a speed sensor can be connected to the navigation control unit.